Search

A new photocurable ladder-like poly(phenyl-co-mercaptopropyl)silsesquioxane (LPPMPSQ) was synthesized in one pot via base catalyzed hydrolysis-polycondensation of a comonomer mixture of phenyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane. Obtained LPPMPSQ was characterized by 1H NMR, FT-IR, 29Si NMR, TGA, and the electrical (k = 3.6) and mechanical properties (surface modulus = 4.9 GPa) found to be suitable for application as a photocurable gate dielectric material.

A novel organic-inorganic hybrid-type ladder-like poly(benzylazide) silsesquioxane (LPBAzSQ) and ladder-like poly(propylazide) silsesquioxane (LPPAzSQ) were synthesized through azidation of ladder-like poly(p-chloromethyl)phenylsilsesquioxane (LPCMPSQ) and ladder-like poly(propylchloro)silsesquioxane (LPPCSQ). The ladder-like structure of the synthesized LPBAzSQ and LPPAzSQ compounds, full substitution of azide groups, and their click chemistry with various functional groups was characterized by 1H NMR, 13C NMR, 29Si NMR, FT-IR, GPC. This new approach for functionalization of ladder-like silsesquioxanes has allowed for insertion of polar functional groups that have yet be examined in silsesquioxane chemistry.

Porphyrin metal complex covered with polystyrene (PS) arm chains was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene from the porphyrin metal (Cu) complex with chain transfer agents (CTA) in the presence of AIBN at 80 °C (PDI < 1.2). Obtained PS covered porphyrin metal complex was then mixed with different molar ratio of styrene-(ethylene-co-butylene)-styrene (SEBS) triblock copolymer to give well-defined morphologies such as cylinder and lamella structures, where the porphyrin metal complex was selectively dispersed into the PS domain of the SEBS triblock copolymer. These materials could be expected to show interesting electroactive properties, because of high dielectric constant (k) and elastomeric property from the porphyrin metal complex and the SEBS triblock copolymer elastomer, respectively.

Well-defined hybrid polymers consisting of organic polymers grafted from inorganic backbone were synthesized by atom transfer radical polymerization (ATRP). Ladder-like structured polysilsesquioxane functioned as both ATRP initiator and hard inorganic backbone, while the organic polymers grafted were hard styrene and soft n-butyl acrylate. Ladder-like structured poly(chloromethylphenylsilsesquioxane) (LCMPSQ) was synthesized using sequential two-step reactions with (ρ-chloromethyl)phenyltrimethxysilane as a monomer in one bath in the presence of K2CO3 as a base catalyst (M w = 6,000). Obtained LCMPSQ was then used as a multi-functional macroinitiator for graft polymerization of styrene (St) or/and n-butyl acrylate (nBA) monomers via ATRP using a CuCl catalyzed system, which gave three types of hybrid graft polymers: poly(styrene-g-silsesquioxane) (PS-g-PSQ), poly(nBA-g-silsesquioxane) (PnBA-g-PSQ) and poly(styrene-ran-nBA-g-silsesquioxane) (PS/nBA-g-PSQ). The hybrid graft polymers were prepared with vari...

UV crosslinkable sulfonated block copolymers of neopentyl p-styrene sulfonate (NSS) and 2-cinnamoylethyl acrylate (CEA) were synthesized by living radical polymerization. For this, the block copolymers of 2-(trimethylsilyl)ethyl acrylate (TMSEA) and NSS were first synthesized by sequential CuBr catalyzed living radical polymerization with 2-bromopropionate (EBP) initiator and N,N,N′,N′-pentamethylethyleneamine (PMDETA) ligand. Obtained well defined block copolymers (polydispersity

Polymethylsilsesquioxane(PMSQ)s with photo-curable groups were prepared by copolymerization of alkoxysilanes. Poly(acryloyl-co-methylsilsesquioxane)(PAMSQ)s of various mole ratio acryloyl group (6 mol%, 12 mol%, 24 mol%, 48 mol%, 100 mol%) were obtained from copolymerization of methyltrimethoxylsilane and 3-(trimethoxysilyl)propyl acrylate. Optical and photonic curable properties were studied by near infrared region spectra, prism coupler, UV-visible spectra, and photo-DSC. The optical losses were below 0.002 dB/cm at 830, 1330, and 1550 nm, respectively. Optical loss was found to be independent of a molar ratio of functional group.

A new type of low-k dielectric material, poly(tridecafluoro1,1,2,2,tetrahydrooctyl-co-phenylsilsesquioxane) (PFCPSQ) was synthesized by hydrolysis and condensation reaction of trimethoxysilyl monomers in the presence of a base catalyst in H2O/THF mixture solvent at 25°C. Chemical compositions, molecular weight, and structure of the obtained PFCPSQs were characterized using 1H NMR, 29Si NMR, FT-IR, and GPC. Dielectric values were examined by a HP-4190 system and a dielectric constant k of 1.92 was obtained.

Physical and optical properties of a series of TAC films with different molecular weight synthesized by acetylation of cotton linter have been investigated. The synthesized TACs had fully acetylated structure in which acetic acid contents was about 62%. Dimensional stability, thermal stability, modulus, tensile strength and elongation at break of TAC film were influenced by the molecular weight of base resin and they increased with the molecular weight. TAC films had good transparency as well as optical isotropy. Especially, optical property and moderate physical properties for protective film application in LCD were achieved above the molecular weight of 250 kg/mol.